CONFIDENTIAL TIBU3516-01

Some customers perceive blow-by and oil mist emitted from the breather as excessive. As a Result they may erroneously conclude that excessive wear has occurred within the engine.

SOLUTION:

Excessive oil consumption complaints; ensure there are no external oil leaks. Have the customer track oil and fuel consumption for a minimum of thirty (30) working days or approximately 300 hours of operation in order to establish a reliable oil-to-fuel consumption ratio. An engine should not be opened up for repair of excessive oil consumption prior to quantifying oil consumption rate. On above engine models average oil consumption for a new engine may vary from 0.12 to 0.25 per cent. Engine load factor, operating temperature, type of oil used, manufacturing tolerances, maintenance and operating practices all impact the rate of oil consumption.

Excessive blow-by and/or oil mist emissions from the breather; To evaluate a customer claim of excessive engine blow-by emissions use the Caterpillar 8T-2700 blow-by indicator tool. Determine actual blow-by at rated speed and load conditions. The approximate blow-by rates for a new engine ranges from 0.5 L/hp min. to 0.6 L/hp min. For example, blow-by of a 300 hp engine could range from 150 L/min to 180 L/min at rated speed and load. Blow-by is considered 'excessive' when it exceeds twice (2x) the normal new engine value.

Reference: Refer to TIBU1196 for blow-by and oil consumption rates relative to 3000 series commercial engines.

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